The mole and the Avogadro constant — practice question

Using numbers only, state the percentage, by volume, of oxygen in clean, dry air.

Using numbers only, state the usual operating temperature, in ^{\circ}C, for the Haber process.

Using numbers only, state how many atoms are present in a diatomic molecule.

Using numbers only, state the greatest number of electrons that the second electron shell of an atom can hold.

Using numbers only, state how many hydrogen atoms are present in an alkane containing 7 carbon atoms.

Using numbers only, state the number of particles in 1 mole, expressed in standard form.